PROJECT SUMMARY Recent advances in understanding the biology of aging have raised the prospect of drug interventions to promote healthy aging in humans. However, such interventions should have essentially no toxicity or side effects. In practice, the throughput of drug testing (currently conducted in animals) is one of the major limitations for identifying interventions to promote healthy aging. Hence, a challenge is to identify candidate drugs able to induce rejuvenation and/or healthy aging, with minimal side effects in a high throughput fashion. Here we propose to take advantage of a novel high content screening approach based on imaging of epigenetic landscape in single cells. To meet the challenge, we propose to take advantage of a novel technique we have developed that is rooted in the analysis of epigenome topography at the single cell level, automated microscopy, and machine learning. ?Microscopic Imaging of Epigenetic Landscapes? (MIEL) captures patterns of nuclear staining of epigenetic marks (e.g. acetylated and methylated histones) and employs machine learning to accurately distinguish between such patterns. Pertinent to this application, we have tested whether MIEL approach is suitable for building a phenotypic cell-based assay for inducers of longevity at the cellular level. Our preliminary results validated MIEL assay for a high content screening application to identify novel candidate pro-longevity compounds. In sum, we have developed and validated a high content cell-based screening assay capable of identifying pro-longevity/healthy aging compounds based on their effect on epigenetic signature. Our specific Aims are as follows: Specific Aim 1. Screen for novel inducers of cellular rejuvenation. Specific Aim 2. Validation of novel inducers of cellular rejuvenation.